Problem with swapDepth

Hi there.
I use the code at the attached txt file to load an xml gallery.
I have 2 buttons which i have convert to movieclips with instance names mc1 and mc2.
I want to make these movieclips to appear in front of the loaded images and not behind.
I tried at the end of my code this:

mc1.swapDepths(myContainer_mc);
mc2.swapDepths(myContainer_mc);

but nothing happens.

Any ideas?

THanks in advance

P.S. I use as2